1. Field of the Invention
The invention encompasses fusion proteins and multimers capable of binding and inhibiting human interferon gamma (IFNγ), as well as therapeutic uses of such polypeptides.
2. Description of Related Art
Interferon gamma (IFNγ) is a lymphokine produced by activated T-lymphocytes. It is known as an immune stimulant because of its ability to activate monocytes and macrophages towards cell killing in vitro (Lee et al. (1983) J Immunol 131:221-2823). U.S. Pat. No. 4,897,264 describes three different types of human IFNγ receptors having molecular weights 90-105 KDa, 140 KDa, and 95-115 KDa. EP 393 502 provides the full-length human IFNγRα sequence of 489 amino acids (SEQ ID NO:1-2) (also known as CD119). U.S. Pat. No. 5,221,789 describes a fragment of human IFNγ receptor alpha (IFNγRα) from position 54-70. Soluble IFNγRα proteins (EP 393 502) and chimeric fusion proteins having a fragment of an IFNγRα receptor fused to an immunoglobulin component (EP 614 981) have been described. WO 95/16036 describes human IFNγ receptor beta (IFNγRβ) having 337 amino acids (SEQ ID NO:3-4) (also known as AF-1).